Three to four percent of hospitalized patients experience an adverse event and 50-65% of these are surgical in nature. Seventy-five percent of surgical adverse events occur in the operating room making it a high impact area to improve patient safety and save lives. We have traditionally measured vulnerability in terms of patient risk factors that predispose to poor outcomes and have equated safety with post-operative outcome. Very little attention has been paid to the system and process by which care is delivered, factors that truly reflect surgical safety. Conversely, many high-risk industries have embraced a human factors approach to sentinel event causation;a theory based on the premise that latent or systemic failures predispose to the occurrence of sentinel events. As such, a human factors approach to the prevention of sentinel events would consist of process changes aimed at eliminating the occurrence of seemingly insignificant systemic deficiencies. There has been recognition in surgical subspecialties that this approach may be useful in reducing the incidence of surgical adverse events, however, to date, there is little data regarding the types of latent failures that predispose to poor clinical outcomes and compromise patient safety. In this study, we intend to compare the intraoperative phase of cardiac surgical care between patients who experience major complications to patients of similar risk profile who do not experience negative outcomes. These analyses will allow for the quantitative and qualitative identification of the types of systemic deficiencies that are most likely to impact clinical outcome in a positive or negative way, thereby allowing for the development of interventions that are most likely to be effective in reducing postoperative complications. PUBLIC HEALTH RELEVANCE: In this study, we aim to use a human factors approach to compare the introperative phase of cardiac surgical care between patients who experience postoperative complications versus those that don't. This will allow for the identification of the most significant systemic factors that impact patient outcome.